Synergistic effects of thalidomide and poly (ADP-ribose) polymerase inhibition on type II collagen-induced arthritis in mice.

The present study investigates synergistic effects of the TNF-alpha inhibitor thalidomide and the poly(ADP-ribose) polymerase (PARP)-inhibitor nicotinic acid amide (NAA) in male DBA/1 hybird mice suffering from type II collagen-induced arthritis. Parameters including the arthritis index, chemiluminescence and anti-collagen antibody titers were used for the assessment of disease activity: The disease courses demonstrated clearly an inhibitory effect of thalidomide. NAA inhibited established collagen arthritis in a dose-dependent manner. The combined application of thalidomide and NAA caused a powerful synergistic inhibition of arthritis. Furthermore, thalidomide and NAA were tested ex vivo for their inhibition of the NADPH oxidase-dependent generation of reactive oxygen species by activated neutrophils and monocytes in unseparated human blood. Our data show that type II collagen-induced arthritis can be suppressed by the simultaneous inhibition of TNF-alpha, PARP, and NADPH oxidase.